Thermostatic switch



Nov. 27, 1934. c. J. WERNER 1,981,934

THERMOSTATIC SWITCH Filed Sept. 3, 1932 2 Sheets-Sheet l CH1. VIN MFA/5HPatented Nov. 27, 1934 UNITED STATES ?ATENT DFFKQE mesnc assignments,ration, Detroit, ware to General Motors ilorpw Mich,

a corporation of Dela- Appllcation September 3, 1932, Serial No. 631.6%

Z Claims.

This invention relates to a switch, and more particularly to athermostatically controlled switch.

It is an object oi this invention to provide a thermostaticallycontrolled switch for controlling a circuit in response totemperaturevariations.

it is also an object oi this invention to provide thermostaticallycontrolled switch that has 319 means for making or breaking or makingand breaking the contacts more rapidly than can be accomplished with theordinary form of thermostatically controlled switches now in use.

Another object of this invention is to provide a 15 switch that whileembodying the above features has one or more adjustments for controllingthe switch action.

Another object oi invention is to provide a switch that may be enclosedin a sealed housing for use with reir i store and in plmes wheremoisture. dust or d a detriment to the use or? cnunsealed sw Stillanother object of this invention is to provide a switch that whilehaving the above advantage is simple in construction, durable, and

flexibility of design.

Further objects and. advantages of the present invention will beapparent from the following description, reference being had to theaccompanying drawings wherein a preferred embodi merit of one form oithe present invention is clearly shown.

the drawings:

Fig.1 shows a side view of one form of switch i embodying the principleof the present invention.

Fig. 2 is a modification oi the switch shown in Figs. 3, 4 and 5 show aswitch embodying a modified form of the present invention and indiilcote different stages in the operation of the switch, some parts beingshown in elevation and some in section.

Fig. 6 is a view of a. modified form of switch embodying the presentinvention and is taken L substantially in the direction of the arrowsand onaline68ofFig.'i.

Fig. 7 is a sectional side view of the switch shown in Fig. 6 andis'taken substantially in the direction of the arrows and on a line '77of c Fig. 6.

With particular reference to Fig. l-a thermostatic member or bimetallicstrip 10 is supported at one end by a support or bracket 12 by means oflugs 16 formed on the end of the bimetallic 5 strip or thermostaticmember 10 that project into oi the coil is connected to the static" 23.A magnetic member or smash is cured to the free end oi the thermo lcEnem .6, and a magnet 32 is so ti o armature 39 that it tends to tactsand 2&3 together by exerting i the armature With particular reference to2, parts hearing; reference numerals similar to those of Fig. l aresimilar perform similar functions. In modification, however, anelectronic-gust having a core 3 .5 and coil 38 is used. @no end.

tact 26 thru the contact carrying a lead The other end of the coil isprovided with a, suitable lead to or connection to the circuitcontrolled by the switch.

With particular reference to-Figs. 3 Q 5, parts bearing referencenumerals similar to those previously used are similar and performsimilar functions. In this modification, a cup-shaped member 42 havingthreads 46 on its outer surface is threaded into an aperture in thebracket or support 12. One end of the cupshaped member 42 has a grooveor slot 48 cut therein to facilitate turning the member in the support12 when making adjustments. The inner surface of the cup-shaped member42 is threaded part way to accommodate 'a threaded adjusting plug 50.The adjusting plug 50 has a slot 52 cut in one end to facilitate turningthe plug for making adjustments. The other end of the cup-shaped member42 has an aperture 54 therein for the accommodation of the pin 56. Oneend or the pin 56 bears against one side of the thermostatic member 10,and the other end 190 has a head 58 thereon that slidably fits into thecup-shaped member 42. A resilient member 60 is interposed between thehead 58 of the pin 56 and one end of the plug 50 to urge the pin againstthe thermostatic member 10. A nut 62 is threaded onto the thread 46 ofthe cup-shaped member 42 to lock the member 42 in place afteradjustments have been made.

With particular reference to Figs. 6 and '7, a

disk of insulating material or insulating support 11 I within theconfines of the cup-shaped member 72, by means of rivets 88. A pin 90having a head 92 on one end that rests against the midportion of thediaphragm '78 projects thru an aperture 94 in the insulating disk '70. Aresilient member 96 intermediate the head 92 and the insulating disk 70urges the head 92 against the diaphragm 78. A supporting member 93 has acurved portion 102 at one end that rests in an aperture 100 in themagnet 86. The other end of the supporting member 96 rests against theend of the pin 90 that projects thru the insulating disk 70. Abimetallic strip or thermostatic member 104, a curved metallic strip 106and a connecting lug 108 are secured to the mid-portion of thesupporting member 98 by means of a rivet 110. A resilient member 112 isinsulated from the cup-shaped member 72 by an insulating member 114, andpresses against the members secured together by the rivet 110 so as tourge the ends of the supporting member 98 against their respec tiverests. An insulator 116 is secured to the curved metallic strip 106 sothat it rests against the end of the cup-shaped member '12 and serves asa rest and to insulate the curved metallic strip 106 from the cup-shapedmember 72.

An armature or magnetic member 118 is secured to the free end or thethermostatic member 104 and magnetically associated with the ends of themagnet 86. An insulator 120 is,secured to the thermostatic member 104near its free end to prevent it from contacting with the cup-shapedmember 72. A contact 122 is also secured to the thermostatic member 104near the free end of that member, and so as to be aligned and makecontact with a stationary contact 124. The stationary contact 124 ismounted on the end of a screw 126 that is threaded into a ring 128 andhas a slot 130 out in its other end to facilitate turning the screw. andmaking adjustments. The ring 128 is mounted in an aperture 136 in thein-v sulating disk '70 and is secured therein .by means 0! a shoulder132 at one of its ends and a riveted or rolled edge 134 at its otherends. A connecting lug 138 interposed between the riveted or rolled edge134 of the ring 128 and theinsulating disk '70, and havingone endof alead 140 connected thereto, serves as a means for making an electricalconnection to the stationary contact 124. The other end of the lead 140is connected to the flanged annular member 74. A plug 142 is threadedinto an aperture 144 in the flanged annular member '74 so as to coverand provide a means for gaining access to the slotted end of the screw126. The washer 146 fits around the plug 142 and provides a tight jointor seal between the plug 142 and the flanged annular member '74. Thescrew 148 is threaded into an aperture 150 in the smaller cup-shapedmember so that its end may be forced against the mid-portion of thediaphragm 78 opposite the head 92 of the pin 90. A nut 152 mounted onthe screw 148 serves to lock the screw into position after it has beenproperly adjusted. Connection is made to the movable contact 122 thruthe thermostatic memher 104, connecting lug 108, a lead 154, a'lug 156,a rivet158 and 2. lug 160. The rivet 158 is insu- 'ture conditions, issubstantially straight.

in the member 72 to form a sealed connecting means.

In the operation of the switch in Fig. '1, the thermostatic member 10,under normal temperachange in temperature in one direction from normalthen causes the thermostatic member 10 to tend to flex with the endsupported by the support 12 as a fixed or anchored end and the screw 18a pivot or fulcrum. However, the pulling force of the magnet 32 upon thearmature or magnetic member 30 transmits a resisting force to the freeend of the thermostatic member that acts against the force developed bythe thermostatic member. After the force developed by the thermostaticmember increases suiiiciently to pass the equilibrium point between theforces, motion of the armature 30 away from the magnet 32 begins, andsince the force due to the magnetic pull varies approximately as thesquare of the distance moved while the force of the thermostatic member,varies approximately as the first power of the distance moved, themotion will be more rapid after once beginning than if the thermostaticmember acted alone to break the connections between the contacts 24 and26. In the same manner, the magnetic force aids in bringing the contactstogether and thus brings about quicker action when closing the circuitthan if the thermostatic member acted alone in returning to itsnon-flexed position after opening the contact.

The operation of the switch shown in Fig. 2 is similar to that of theswitch shown in Fig. 1, except that an electromagnet is used and themagnet coil 36 is connected in the, circuit controlled by the contacts24 and 26. Hence, the magnetic force will only be ,eifective when thecontacts are together and the circuit thru the coil 36 is closed. Thisprovides for quicker breaking of the contacts substantially as explainedfor Fig; 1, except that when the circuit breaks, the magnetic force is'substantially completely in effective in restraining the action of thethermostatic member.

In the switch shown in Figs. 3, 4 and 5, Fig. 3 shows the normalposition of the elements of the switch. As the temperature changes, thethermostatic member 10 flexes against the force of resilient member 60and this forces the pin 56 into the cup-shaped member 42 until thethermostatic member 10 rests against the end of the cup-shaped member 42as shown in Fig. 4. The end of the cup-shaped member 42 then acts as afulcrum and the flexing force develops to overcome the magnetic force aspreviously explained for Fig. 1.' However, after motion starts theurging force of the resilient member 60 aids the flexing force inseparating the contacts, and the motion of the pin 56 serves toseparatethe contacts farther than would a flxed fulcrum such as that used on aswitch on Fig. 1, and as indicated in Fig. 5. By turning the cup-shapedmember 42 in its support, the height of the flxed fulcrum may be varied,and hence the distance that the thermostat must move to contact with thefulcrum may be changed. Then, the urging force of the resilient member60 may be varied by turning the plug 50. The adjusting of the plug 50varies the force that tends to urge the thermostatic member 10 away fromthe fulcrum formed by the cup-shaped member 42, and also varies theadditional force due to the resilient member 60 that aids in theseparation of the contact.

With particular reference to Figs. 6 and 7, the thermostatic member 104is mounted on a supporting member 98, which supporting member has onefixed support for its curved end 102 and an adjustable support for itsother end formed by the pin 90. By turning the screw 148, it may becaused to flex the diaphragm 78 and thus move the pin 90 that is urgedagainst thediaphragm by the action of the resilient member 96. Movementof the pin 90 varies the position oi one end of the supporting member 98and rotates that member about its curved and 162, which action istransmitted to the thermostatic member 104 to vary its normal position.The resilient member 112 urges the supporting member 98 against themagnet 36 and the pin 90, while the curved metallic strip ice and theinsulator lid serve to steady the thermostatic memoer and prevent itfrom coming contact with the cupshaped member '32,

The stationary contact 1% may be adjusted toward or away irom contact122 that mount ed on the thermostatic member by removing plug 142 andturning the screw 126. fine ment of the stationary contact 124 VEiZlC-isdistance between the armature or magnetic member 118 and the ends of themagnet 86, and hence varies the force applied to the armature 118 by themagnet 85 the contacts closed. The closer armature is to the ends of themagnet the greater will the necessary flexing iorce developed o theirmostatic member to open or eon= tacts. The action operation of teesimilar to those previously expla ing formed by the c ndition iiangedannular is lit shaped member so prose vent moisture, dust, or grease iin g" into the switch and imparing action in of its various adoptions,

While the form of invention as herein cons; ferred form, it is to iceiuiderstoc forms might be adopted, coming scope oi the claims whichiollow,

What is claimed is as follows:

i. A switch, comprising combine mostatic member; means for cuppathermostatic member so that it may sponse to temperature change; coopertaots, one of which contacts is move sponse to the flexing of saidthermostat member; means for supporting the other oi said-contacts;adjusting means for adjusting the normal position of said thermostaticmember; an arme-= ture attached to said thermostatic member; a magnetfor applying a force to said armature; and a housing for said switchcomprising, a cup= shaped member, a flanged annular member adjoiningsaid cup-shaped member, a diaphragm, a

smaller cup-shaped member placed over said diaphragm and secured to saidflanged member, and

means secured to said smaller cup-shaped mem her for actuating saidadjusting means by flexing said diaphragm.

2. A switch, comprising in combination, a

thermostatic member; means for supporting said ber; means for supportingthe other of said contacts; adjusting means for adjusting the normalposition of said thermostatic member; and a housing for said switchcomprising, a cup-shaped member, a flanged annular member adjoining saidcup-shaped member, a diaphragm, a smaller cup-shaped member placed oversaid diaphragm and secured to said flanged member, and means secured tosaid smaller cup-shaped member for actuating said adjusting means byflexing said diaphragm.

3. A switch comprising, in combination, a thermostatic member; means forsupporting said thermostatic member so that it may flex in response totemperature change, said supporting means including a movable pivotallymounted member to which the thermostatic member is secured; cooperatingcontacts, one oi which contools is movably mounted so to move inresponse to the flexing of said thermostatic meniber; means forsupporting the other of said 35 contacts; a housing providing enclosurefor "the switch elements and comprising s tially cup-shaped member, aflanged an ular member adjoining said cup member, a diaphragm offlexible mater secured to the flanged annular member to form rstantially cup-shaped member substantially cup-shaped menisci diaphragm;adjusting means out the third cup-shaped mem diaphragm; and meanspiiragin and movable pivotally for adjusting the position of otallymounted member in res, phragm ilexure caused by eoijus d. A switchcompris ng,

one including a movable pivo member to which the thcrmoi secured;cooperating contacts, tacts is movably mounted so a sponse to theflexing of said leer; means for supporting" the contacts; a housingproviding switch elements and comp tially cup-shaped. member, a memberadjoining said cup- '15; diaphragm of flexible material scour flangedannular member to i n a scoop substantially cup-shaped mem e therewith,a third substantially cup-shaped member said diaphragm; adjusting meansecu/ending thru the third cup-shaped member f r flexing the diaphrugm;and means intermediate the s aphzagm and movable pivotally mounted memofor adiusting the position oi the movable pivotally mounted member inresponse the diaphragm -dexure caused by said adjusting no? he, saidmeans intermediate the diaphragm and movable pivotally mounted memberbeing resiliently urged. against said diaphragm.

5. A switch comprising, in combination, support member; a stationarycontact adjustahly mounted on the support member; a magnet secured tothe support member and having magnetic pole tips near the stationarycontact; a thermostatic member having a contact mounted thereon that isengageable with said stationary contact, and an armature also mountedthereon and magnetically associated with said magnet; means comprising amovable member for supporting said thermostatic member so that it willflex in response to temperature change to 150 mean said eflectengagement or disengagement of the contacts; a substantially cup-shapedmember secured to the support member and providing an enclosure over themagnet and thermostatic element; a flanged annular member secured to theopposite side of the support member from said cup-shaped member; adiaphragm of flexible material secured to the flanged annular member toform a second cup-shaped member therewith; a third substantiallycup-shaped member cover ing said diaphragm; adjusting means extendingthru the third cup-shaped member for flexing the diaphragm; and meansintermediate the diaphragm and movable member for adjusting the positionof the movable member in response to the diaphragm fiexure efiected bysaid adjusting means.

6. A switch comprising, in combination, a

- thermostatic member; means for supporting the for further flexure ofthe thermostatic member in the same direction until the thermostaticmember separates the contacts; said resilient means aiding in theseparation 01' the contacts; and magnetic means tending to holdsaidcontacts in engagement.

7. A switch comprising, in combination, a support member; a thermostaticmember mounted at one end to the support member and having a firstcontact mounted near its other end, said thermostatic member beingadapted to flex in response to temperature changes; a second contactengageable with the first contact; magnetic means tending to hold saidcontacts in engagement; means applying a force to thethermostatic memberintermediate the ends thereof, whichmeans resists fiexure of thethermostatic member in one direction; a stop for limiting flexure of thethermostatic member against the means and providing a tulcrum forfurther flexure of the thermostatic member.

'cnnvm J. WERNER.

